Get MCedit, open the map in MCedit, do: Ctrl+s if that doesn't work try reloading the chunks in MCedit, open the server, DONE!
You also might need to reload the chunks in MCedit... I had this MANY times
Reload the chunks in MCedit, or delete [world]_nether. worked for me.
I used to have a nether world, but now i don't. however, minecraft edit help me fix it (the ctrl+s+alt+f4 thing)
Can you send a download link? Minecraft Forums is closed down... btw, what does ctrl + s + f4 mean in MCedit?
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